Visual line input apparatuses have been proposed as an interface between an apparatus, such as a vehicular apparatus and a mobile terminal, and a human. For example, Patent Literature 1 discloses that a visual line detector is arranged at the bottom side of a navigation device arranged at the center of an instrument panel in a vehicle; the user's gazing position at a display screen of the navigation device is detected by the visual line detector; and a visual line input to the navigation device is carried out.